The present invention relates to a new and improved apparatus for stacking flat products arriving in an imbricated stream, preferably printed products which constitute relatively stiff products.
In its more particular aspects, the present invention relates specifically to a new and improved apparatus for stacking products arriving in an imbricated stream, preferably printed products, which contains at least one stacker device possessing at least one periodically emptiable stacker compartment for forming stacks. An infeed device infeeds the products to the stacker compartment and an infeeder is arranged forwardly of the infeed device for the infeed of the products to the infeed device.
With such type of stacking apparatus known from German Patent Publication No. 2,752,513 (and the corresponding British Pat. No. 1,568,752, published June 4, 1980) the infeeder is constituted by a transport device containing grippers arranged behind one another in its conveying direction, which grippers individually seize the printed products and then upon release thereof free such products. In the conveying direction of this infeeder there are arranged at a spacing behind one another two stacker units which are alternatingly loaded with printed products. Leading to the stacker chute of each stacker unit is a conveyor band arranged below the infeeder and laterally of the stacker unit, this conveyor band terminating shortly before the stacker chute. Viewed in the conveying direction of the infeeder there is arranged at a spacing behind each stacker unit a release device which can be switched-on and switched-off, and which in the switched-on condition opens the grippers moving therepast. The printed products released by the grippers are taken-over by the related conveyor band and transported towards the stacker chute. Due to an alternate switching-on and switching-off of the release devices there is either loaded the one or the other stacker unit.
The printed products which are infed by the infeeder in an imbricated formation to the conveyor bands are again deposited in an imbricated formation upon the conveyor bands. Consequently, the printed products are moved by the conveyor bands likewise in an imbricated stream towards the stacker chutes and so-to-speak pushed into the same. After release by the conveyor band the printed products drop into the stacker chute. The point in time of such release cannot, however, be exactly determined and also not readily influenced. Therefore, it is possible that the products will not drop into the stacker chute during uniform time intervals, which, under circumstances, can have a disadvantageous effect upon the quality of the product stack.
The products which are, as mentioned, propelled by the conveyor bands into the related stacker chute, are moved with their leading edge against a wall of the stacker chute, by means of which they are then stopped in their movement imparted by the conveyor band. This impact of the products against the stacker chute wall can lead to damage of the products. The previously explained principle of pushing the products into the stacker chute in an imbricated formation likewise is used by the most general other known stacker devices.